1. Field of the Invention
The present invention relates to a 6-component load cell capable of measuring triaxial force components (Fx, Fy, Fz) and triaxial moment components (Mx, My, Mz) simultaneously.
2. Description of the Prior Art
In the prior art, a load cell or a force measuring sensor is designed to measure a uniaxial force so that in order to obtain reliable sensing results, the typical load cell has to be installed in a direction where the force to be measured acts. However, due to the recent trend of both automation of mechanical systems and development of machine tools, it is necessary to precisely measure multiaxial force and moment components simultaneously. In an effort to achieve such a necessity of multiaxial measurement, a plurality of load cells may be installed in different axes. However, the above method using several cells is problematic in that it is space consuming thus being unadaptable in the event of limited space. In this regard, a force measuring sensor given the term "multi-component load cell" is proposed and used for measuring multiaxial force and moment components simultaneously.
Several-types of multi-component load cells are proposed in the prior art. Sceinman proposes a multi-component load cell, in which four deflection bars cross at right angles, with 16 semiconductor strain gauges individually being installed on each side wall of each deflection bar and being formed into a bridge. The output voltage of each strain gauge is in proportion to the force component acting in a direction perpendicular to the surface of each strain gauge. Therefore, it is possible to measure triaxial force and moment components simultaneously by appropriately doing sums of the output voltages of the 16 strain gauges. The Sceinman's load cell is advantageous in that it is somewhat easily produced through a simple process but is problematic in that it has a measuring error of about 5% thus having an inferior precision. Another problem of the Sceinman's load cell resides in that it does not directly measure the force and moment components, but arithmetically measures the components, thus being time consuming.
Yabaki proposes a multi-component load cell, in which 8 parallel leaf springs form an elastic crossing structure with 6 Wheatstone bridges constituting 24 thin strain gauges. The Yabaki's load cell directly measure the triaxial force and moment components without processing an arithmetic calculation. However, the above load cell has a measuring error of 2% while measuring the force components and 3-5% while measuring the moment components.
Hatamura proposes a 6-component load cell, which comprises a force component measuring parallel plate and a moment measuring radial plate. The Hatamura's load cell has a high precision with a measuring error of about 2% while measuring force components and about 3% while measuring moment components. However, the above load cell is problematic in that it is difficult to produce the cell.